A major obstacle to the identification and analysis of genes involved in cell transformation and tumor progression is the need for better methods for capture and stabilization of transcripts in tumor cells. Presently, cDNA populations synthesized from tumor cells are likely to incomplete, in terms of both the length of the product, and the representation of rare sequences. Therefore, cDNA probes and libraries, as well as the amplified products produced from biased and incomplete RNA populations, are less likely to accurately reflect the gene expression profile of the tumor. PROPOSED COMMERCIAL APPLICATION: When developed, in vivo cDNA synthesis is expected to be a broadly enabling technology, with applications in cDNA synthesis, cDNA cloning, sample preparation and stabilization, gene expression analysis and gene discovery, and molecular diagnostics.